Distributing arrangement for shot-fed soot cleaning systems

ABSTRACT

The present invention relates to the cleaning of gas-swept beating surfaces in heat exchanging apparatus by the scouring action of cleaning particles, such as steel shot, which are scattered over the heating surfaces by a distributing member from which the cleaning particles rebound. The invention provides, in combination with a distributing member as already known in the art an annulus-shaped distributing element disposed below the said distributing member and substantially concentrically thereto. By this arrangement a more uniform distribution of the cleaning particles is attained, particularly when the intensity of cleaning is great, i.e. cleaning particles are cycled at a high rate through the heat exchanging apparatus.

United States Patent [72] inventors Borje Fransman Sollentuna: Per Thorson. Stockholm, both of, Sweden [21] Appl. No. 874,942

[22] Filed Nov. 7, 1969 [45] Patented July 20, 1971 [73 Assignee Husqvarna licensing AB, Huskvarna,

Sweden [32] Priority Nov. 8, 1968 [33] Sweden [31] 15,175/68 [54] DISTRIBUTING ARRANGEMENT FOR SHOT-FED SOOT CLEANING SYSTEMS 3 Claims, 2 Drawing Figs.

[52] US. Cl 165/95, 15/95, 122/395,134/17 [51] int. Cl F28g 13/00 [50] Field of Search 165/95; 122/395; 15/95; 134/17 [56] References Cited UNITED STATES PATENTS 2,765,588 10/1956 Puhr-Westerheide 165/95 X 2,809,018 10/1957 Broman 165/95 2,946,569 7/1960 Kirkby r. 165/95 2,993,681 7/1961 McColl 165/95 3,302,699 2/1967 Hedentorp et al. 165/95 Primary Examiner-Albert W. Davis, Jr. Attorney-Holman, Glascock, Downing and Seebold ABSTRACT: The present invention relates to the cleaning of gas-swept beating surfaces in heat exchanging apparatus by the scouring action of cleaning particles, such as steel shot, which are scattered over the heating surfaces by a distributing member from which the cleaning particles rebound. The invention provides, in combination with a distributing member as already known in the art an annulus-shaped distributing element disposed below the said distributing member and substantially concentrically thereto. By this arrangement a more uniform distribution of the cleaning particles is attained, particularly when the intensity of cleaning is great, i.e. cleaning particles are cycled at a high rate through the heat exchanging apparatus.

PATENTED JUL20 IHTI FIG.2

DISTRIBUTING ARRANGEMENT FOR SHOT-FED SOOT CLEANING SYSTEMS For cleaning during operation of heating surfaces in heat exchangers a method is widely used by which the heating surfaces are subjected to the scouring action of cleaning particles, commonly steel shot, which are distributed over the heating surfaces by being dropped against one or more distributing members, and after rebounding from the latter drop on to the heating surfaces removing dust, soot and other deposits therefrom, and are subsequently recycled.

When cleaning particles shall be circulated in large quantities at a high rate, as necessary in many plants to keep the heating surfaces effectively cleaned, the distribution pattern of the cleaning particles, after the latter have hit against the distributing member, may be rather nonuniform. Especially those cleaning particles striking the distributing member tangentially may become concentrated to certain zones of the heating surfaces, causing damage in the long run, whereas other portions of the heating surfaces may become starved of cleaning particles and thus will not be adequately cleaned.

It is an object of the present invention to provide distributing means which eliminate the said drawbacks and which afford a more uniform distribution. According to the invention these distributing means comprise in combination a distributing member having an upward-facing convex active surface and below this member, substantially concentrically therewith, an annulus-shaped distributing element.

Distributing members with-a convex, preferably spherical active surface are priorly known. Such a device is disclosed, for example, in US. Pat No. 2,809,018.

Through the combination of such a known distributing member with an annulus-shaped element disposed below the former, concentrically therewith, the difficulties referred to and which arise when cleaning particles are cycled at a high rate can be mastered, and a uniform distributing pattern may be attained even in those cases.

An embodiment of a cleaning particle distributing arrangement according to the invention will be described hereinafter,

reference being made to the drawing in which FIG. I is a side elevation view of a combined distributing member and FIG. 2 is atop plan view, partly in section along the line ll-Il in FIG. 1.

The combined distributing member illustrated in the drawing will be mounted within a heat exchanger below the top of the latter and some distance above the uppermost gas-swept heating surfaces thereof. Means will be provided for cycling cleaning particles through the heat exchanger in a closed circuit. The general arrangement may be such as described and illustrated, for example, in US. Pat. No. 2,665,118 and No. 2,665,] 19 which disclose heating surface cleaning systems illustrative of the art although provided with distribution members of a rotary type.

The cleaning particles are fed downwards through a vertical pipe which sealingly passes through the top of the heat exchanging apparatus and fonns part of a circuit for cycling cleaning particles through the heat exchanger. The bottom end of pipe 10 is surrounded by a flange or collet II, and a depending angle-shaped bracket 12 is rigidly secured by one of its shanks to said collet 11. The other shank of the bracket 12 extends substantially horizontally and terminates in a cylindrical member 13 rigidly secured thereto. A part-spherical distributing member B4 of a hard, wear-resistant material is mounted with its convex surface facing upwards on the top face of the cylindrical member I3, in directly opposed relationship to the mouth of the pipe 10. Cleaning particles fed through the pipe I0 will hit against the convex surface of distributing member 14 to be scattered thereby over the heating surfaces of the heat exchanger.

Some cleaning particles which hit the distributing member 14 at points close to the outer edge thereof tend to be concentrated toward certain portions of the heating surfaces when the intensity of particle bombardment :is great.

According to the present invention such particles are intercepted in their paths and scattered in new directions by an annular element 15 of a wear-resistant material which is located below the distributing member I4, concentrically thereabout. The annular element 15 is rigidly secured at one side to the bracket I2 and at the opposed side to the cylindrical member 13 by means of a strut member 16. The components making up the device described above are preferably joined together by welding.

The dimensions and position of the annular element 15 is chosen in such a way that it will intercept in the first place those cleaning particles which hit the distributing member glancingly, as already described, and will scatter such particles in different directions, avoiding thus the tendency for particle concentration to certain zones which would incur the hazard of a too vigorous attack on the heating surfaces whereas the area directly below the distributing member would be subjected to the action of only a comparatively small number of particles.

The annulus-shaped element 15 has been illustrated as having a circular cross section shape, but each other suitable shape may be used, instead.

If the cross section area of the heat exchanger exceeds a size for which a single distributing arrangement will be adequate two or more spaced such arrangements may be provided.

What we claim is:

I. In a heat exchanging apparatus comprising gas-swept heating surfaces the provision of means for feeding cleaning particles and means for intercepting and scattering cleaning particles, such as steel shot, said last named means comprising in combination a distributing member having a convex active surface and below this member substantially concentrically thereabout an annular distributing element.

2. Means as claimed in claim I wherein the said distributing member is a part-spherical body and said annular distributing element is of a toroidal shape.

3. In a heat exchanging apparatus, a cleaning particle intercepting and scattering arrangement'comprising an essentially vertical feed pipe for cleaning particles; flange means at the bottom end of the said feed pipe; bracket means rigidly attached to said flange means and extending downwards and inwards below said feed pipe; a support member rigidly attached to said bracket means directly opposite said feed pipe; at partspherical distributing member mounted on top of said support member, and a toroidal annular distributing element being of a width greater than that of the part-spherical member and disposed below the latter, substantially concentrically thereto, said element being rigidly attached to said bracket means and said support means. 

1. In a heat exchanging apparatus comprising gas-swept heating surfaces the provision of means for feeding cleaning particles and of means for intercepting and scattering cleaning particles, such as steel shot, said last named means comprising in combination a distributing member having a convex active surface and below this member substantially concentrically thereabout an annular distributing element.
 2. Means as claimed in claim 1 wherein the said distributing member is a part-spherical body and said annular distributing element is of a toroidal shape.
 3. In a heat exchanging apparatus, a cleaning particle intercepting and scattering arrangement comprising an essentially vertical feed pipe for cleaning particles; flange means at the bottom end of the said feed pipe; bracket means rigidly attached to said flange means and extending downwards and inwards below said feed pipe; a support member rigidly attached to said bracket means directly opposite said feed pipe; a part-spherical distributing member mounted on top of the said support member, and a toroidal annular distributing element being of a width greater than that of the part-spherical member and disposed below the latter, substantially concentrically thereto, said element being rigidly attached to said bracket means and said support means. 